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64 lines
2.0 KiB
C
64 lines
2.0 KiB
C
/*
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* Canopus common routines
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* Copyright (c) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdint.h>
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#include "libavutil/rational.h"
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#include "avcodec.h"
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#include "bytestream.h"
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#include "canopus.h"
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int ff_canopus_parse_info_tag(AVCodecContext *avctx,
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const uint8_t *src, size_t size)
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{
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GetByteContext gbc;
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int par_x, par_y, field_order;
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bytestream2_init(&gbc, src, size);
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/* Parse aspect ratio. */
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bytestream2_skip(&gbc, 8); // unknown, 16 bits 1
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par_x = bytestream2_get_le32(&gbc);
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par_y = bytestream2_get_le32(&gbc);
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if (par_x && par_y)
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av_reduce(&avctx->sample_aspect_ratio.num,
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&avctx->sample_aspect_ratio.den,
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par_x, par_y, 255);
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/* Short INFO tag (used in CLLC) has only AR data. */
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if (size == 0x18)
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return 0;
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bytestream2_skip(&gbc, 16); // unknown RDRT tag
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/* Parse FIEL tag. */
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bytestream2_skip(&gbc, 8); // 'FIEL' and 4 bytes 0
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field_order = bytestream2_get_le32(&gbc);
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switch (field_order) {
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case 0: avctx->field_order = AV_FIELD_TT; break;
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case 1: avctx->field_order = AV_FIELD_BB; break;
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case 2: avctx->field_order = AV_FIELD_PROGRESSIVE; break;
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}
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return 0;
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}
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